On Saturday, retiring Tennessee Republican Sen. Bob Corker tweeted that he was working with “like-minded” senators on the issue, but whether there will be a large enough coalition to force a change isn’t clear yet.

“I am working with like-minded Republican senators on ways to push back on the president using authorities in ways never intended and that are damaging to our country and our allies. Will Democrats join us?” tweetedCorker, who chairs the Senate Foreign Relations Committee.

“I hope we pull back from the brink here because these tariffs will not be good for the economy, and I worry that it will slow, if not impeded significantly, the progress we were making economically for the country,” Senate Majority Leader Mitch McConnell said during an event in Kentucky last week.

But, confronting Trump — especially just months ahead of the midterms — carries its own risks. So far, Republican leaders — including McConnell, House Speaker Paul Ryan, House Ways and Means Chairman Kevin Brady and Senate Finance Committee Chairman Orrin Hatch — have all sounded the alarm, but there’s little evidence that they’d swiftly move legislation to roll back the trade authority of the administration.

“This is a big mistake,” said Sen. Lamar Alexander, a Tennessee Republican, summing up GOP opposition to Trump’s tariffs.

Sen. Chuck Grassley, a Republican who hails from the agriculture-heavy state of Iowa, told reporters Monday there were questions surrounding whether these specific tariffs would improve national security, a rationale Trump has cited for the tariffs and that Canada’s finance minister described as “absurd.”

“The question is, is he using it for legitimate national security purposes?” said Grassley, who chairs the powerful Senate Judiciary Committee. “And I’m sure he feels he is. But I think there is some question about that.”

Asked if the tariffs were concerning, Grassley responded, “I would want a President to try to get us a better deal if he could on trade. But I’m also nervous because I’ve seen (Jimmy) Carter and (Ronald) Reagan and George W. Bush put such tariffs on and then when there is retaliation, it’s against agriculture and that’s very concerning to me.”